A trial was carried out with 48 Duroc × (Landrace × Large White) pigs intended for dry-cured ham; 24 males and 24 gilts of 46.3 and 42.9 kg BW, respectively. For that end, surgically castrated males are used to avoid sexual odour and minimum levels of fat thickness, measured at Gluteus medius muscle (GM; >16 mm), are required to improve the ripening process and ham quality. Currently, the main problems are the future prohibition in EU of this type of castration and the lack of fat in gilts. The effect of immunization against GnRH on growth performances and carcass quality was evaluated. There were 4 experimental treatments; surgically castrated males (CM), immunocastrated males (IM), entire gilts (EG) and immunocastrated gilts (IG). The CM had been castrated at 5 d of age. Inmunization was carried out in both sexes with 2 injections of Improvac (Zoetis) with an interval of 4 weeks (1st: 44.6 kg BW, 2nd: 70.6 kg BW, as average). The replicate was a pen with 3 pigs (n = 4) for performance traits and the animal (n = 12) for carcass traits. A commercial diet, based on barley, wheat, and vegetable meals and containing 13.74 MJ DE/kg, 14.1% CP, and 0.75% Lys, was provided ad libitum through the trial. Pigs were slaughtered at 127 kg BW. Data were analyzed by ANOVA and the statistical model included the sex as main effect. Duncan test was used to compare pairs of means. From 1st to 2nd injection, the EG grew faster than IG with CM and IM being intermediate (P < 0.001) but this effect disappeared after. At the end of the trial, the CM had higher feed:gain ratio than the other treatments (P < 0.05). No effect of immunocastration was observed on carcass yield but the IG had wider fat depth at GM and lower lean yield than EG with CM and IM being intermediate (P < 0.05). Intramuscular fat content was not affected by sex. It is concluded that the immunization against GnRF might be a good strategy to improve some traits desirable in pigs intended for dry-cured ham because, in gilts, it increased fat depth and, in males, it reduced feed:gain ratio in comparison with those surgically castrated.